The objectives for this project are (1) to study the somatosensory activation of cortical neurons in the second somatic sensory, insular and posterior insular regions in primates; (2) to study the connections of physiologically defined portions of these cortical regions with autoradiographic and retrograde cell labeling techniques; and (3) to reexamine the neural responses from this cortex in awake, behaving animals conditioned to discriminate tactile or painful thermal stimuli. It is expected that these studies will help to define the cortical locus for pain and temperature sensations since these cortical regions receive inputs from portions of the thalamus known to receive projections from the spinothalamic tract. An additional series of experiments have examined the oganization of efferent projections to the thalamus and spinal cord from several brainstem nuclei that are associated with relaying somatosensory, especially temperature and pain, information.